Thermostable FGF2 for Stem Cell (hESC or iPS) Culture

FGF2 (also known as FGF-basic or bFGF) is required in stem cell cultures to maintain the stem cells in an undifferentiated and pluripotent state. However, FGF basic is unstable, requiring daily media changes with fresh addition of FGF basic, which is costly, tedious and time consuming. To overcome this problem, a thermal stable version of FGF basic has been developed to support a 2-day media change protocol instead of daily media change. The 2-day media change protocol relieves stem cell researchers from coming back to the lab over the weekend, making it an ideal choice for stem cell researchers. Thermostable FGF2 was carefully engineered for enhanced stability in culture media, without affecting its biological functions.

Stability of thermostable FGF2 (FGFbasic-TS) in cell culture media

When cultured in a typical stem cell culture media at 37°, a considerable amount (35%) of Thermostable FGF2 (SPEED SKU# SDP1025) remains intact in the media after 2 days of culture, while regular FGF2 (SPEED SKU# YCP1143) is undetectable after day 1. The results suggest thermostable FGF2 degrades roughly 3 times more slowly than regular FGF basic.

Resistance of thermostable FGF2 to enzymatic digest

When exposed to trypsin, FGF2 is significantly degraded after 4.5 hours, while FGF2-TS (thermostable) levels are only slightly reduced. Of note, Heprin protects FGF2 and FGF2-TS from trypsin digestion. Thermostable FGF basic is more resistant towards proteolytic degradation compared to FGF basic.

Thermostable FGF2 (FGFbasic-TS) maintains pluripotency of stem cells with 2-day feeding schedule

Using a two-day feeding protocol, pluripotency of stem cells is effectively maintained after 10 passages, regardless that the cells are human embryonic stem cells (hESC) or induced pluripotent stem cells (iPSC); passaged using a non-enzymatic passaging solution (XFPS) or using a collagen-based reagent (CG); cultured in chemically defined matrix (XFM) or in Matrigel (MG). Pluripotency is confirmed by cytometric analysis of stem cell markers including SSEA-4, Tra1-60, Tra1-81 and Oct3/4.

Thermostable FGF2 maintains FGF2’s activity in promotion of stem cell proliferation

With a two-day feeding protocol, iPSC cell cultures maintained healthy growth characteristics even after 10 passages. The picture below shows iPS cells at the 2nd and 6th day of culture, respectively.

Thermostable FGF2 (FGFbasic-TS) does not induce genetic abnormalities

Stem cell cultures are known to develop genetic abnormalities during long-term culture. On a 2-day feeding schedule with 10 mg/mL FGFbasic-TS, an iPS cell line remains normal in karyotype analysis after the 10th passage.